/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.templates;

import javax.xml.transform.TransformerException;

import wx.xml.xalan.xalan.res.XSLTErrorResources;
import wx.xml.xalan.xalan.transformer.TransformerImpl;
import wx.xml.xalan.xml.utils.QName;
import wx.xml.xalan.xpath.XPath;
import wx.xml.xalan.xpath.XPathContext;
import wx.xml.xalan.xpath.objects.XObject;
import wx.xml.xalan.xpath.objects.XRTreeFrag;
import wx.xml.xalan.xpath.objects.XString;

/**
 * Implement xsl:with-param.  xsl:with-param is allowed within
 * both xsl:call-template and xsl:apply-templates.
 * <pre>
 * <!ELEMENT xsl:with-param %template;>
 * <!ATTLIST xsl:with-param
 *   name %qname; #REQUIRED
 *   select %expr; #IMPLIED
 * >
 * </pre>
 *
 * @xsl.usage advanced
 * @see <a href="http://www.w3.org/TR/xslt#element-with-param">element-with-param in XSLT Specification</a>
 */
public class ElemWithParam extends ElemTemplateElement {
    static final long serialVersionUID = -1070355175864326257L;
    /**
     * This is the index to the stack frame being called, <emph>not</emph> the
     * stack frame that contains this element.
     */
    int m_index;
    int m_qnameID;
    /**
     * The "select" attribute, which specifies the value of the
     * argument, if element content is not specified.
     *
     * @serial
     */
    private XPath m_selectPattern = null;
    /**
     * The required name attribute specifies the name of the
     * parameter (the variable the value of whose binding is
     * to be replaced). The value of the name attribute is a QName,
     * which is expanded as described in [2.4 Qualified Names].
     *
     * @serial
     */
    private QName m_qname = null;

    /**
     * Get the "select" attribute.
     * The "select" attribute specifies the value of the
     * argument, if element content is not specified.
     *
     * @return Value of the "select" attribute.
     */
    public XPath getSelect() {
        return m_selectPattern;
    }

    /**
     * Set the "select" attribute.
     * The "select" attribute specifies the value of the
     * argument, if element content is not specified.
     *
     * @param v Value to set for the "select" attribute.
     */
    public void setSelect(XPath v) {
        m_selectPattern = v;
    }

    /**
     * Get the "name" attribute.
     * DJD
     *
     * @return Value of the "name" attribute.
     */
    public QName getName() {
        return m_qname;
    }

    /**
     * Set the "name" attribute.
     * DJD
     *
     * @param v Value to set for the "name" attribute.
     */
    public void setName(QName v) {
        m_qname = v;
    }

    /**
     * Get an integer representation of the element type.
     *
     * @return An integer representation of the element, defined in the
     * Constants class.
     * @see wx.xml.xalan.xalan.templates.Constants
     */
    public int getXSLToken() {
        return Constants.ELEMNAME_WITHPARAM;
    }


    /**
     * Return the node name.
     *
     * @return the node name.
     */
    public String getNodeName() {
        return Constants.ELEMNAME_WITHPARAM_STRING;
    }

    /**
     * This function is called after everything else has been
     * recomposed, and allows the template to set remaining
     * values that may be based on some other property that
     * depends on recomposition.
     */
    public void compose(StylesheetRoot sroot) throws TransformerException {
        // See if we can reduce an RTF to a select with a string expression.
        if (null == m_selectPattern
            && sroot.getOptimizer()) {
            XPath newSelect = ElemVariable.rewriteChildToExpression(this);
            if (null != newSelect)
                m_selectPattern = newSelect;
        }
        m_qnameID = sroot.getComposeState().getQNameID(m_qname);
        super.compose(sroot);

        java.util.Vector vnames = sroot.getComposeState().getVariableNames();
        if (null != m_selectPattern)
            m_selectPattern.fixupVariables(vnames, sroot.getComposeState().getGlobalsSize());

        // m_index must be resolved by ElemApplyTemplates and ElemCallTemplate!
    }

    /**
     * Set the parent as an ElemTemplateElement.
     *
     * @param p This node's parent as an ElemTemplateElement
     */
    public void setParentElem(ElemTemplateElement p) {
        super.setParentElem(p);
        p.m_hasVariableDecl = true;
    }

    /**
     * Get the XObject representation of the variable.
     *
     * @param transformer non-null reference to the the current transform-time state.
     * @param sourceNode  non-null reference to the <a href="http://www.w3.org/TR/xslt#dt-current-node">current source node</a>.
     * @return the XObject representation of the variable.
     * @throws TransformerException
     */
    public XObject getValue(TransformerImpl transformer, int sourceNode)
        throws TransformerException {

        XObject      var;
        XPathContext xctxt = transformer.getXPathContext();

        xctxt.pushCurrentNode(sourceNode);

        try {
            if (null != m_selectPattern) {
                var = m_selectPattern.execute(xctxt, sourceNode, this);

                var.allowDetachToRelease(false);

                if (transformer.getDebug())
                    transformer.getTraceManager().fireSelectedEvent(sourceNode, this,
                        "select", m_selectPattern, var);
            } else if (null == getFirstChildElem()) {
                var = XString.EMPTYSTRING;
            } else {

                // Use result tree fragment
                int df = transformer.transformToRTF(this);

                var = new XRTreeFrag(df, xctxt, this);
            }
        } finally {
            xctxt.popCurrentNode();
        }

        return var;
    }

    /**
     * Call the children visitors.
     *
     * @param visitor The visitor whose appropriate method will be called.
     */
    protected void callChildVisitors(XSLTVisitor visitor, boolean callAttrs) {
        if (callAttrs && (null != m_selectPattern))
            m_selectPattern.getExpression().callVisitors(m_selectPattern, visitor);
        super.callChildVisitors(visitor, callAttrs);
    }

    /**
     * Add a child to the child list. If the select attribute
     * is present, an error will be raised.
     *
     * @param elem New element to append to this element's children list
     * @return null if the select attribute was present, otherwise the
     * child just added to the child list
     */
    public ElemTemplateElement appendChild(ElemTemplateElement elem) {
        // cannot have content and select
        if (m_selectPattern != null) {
            error(XSLTErrorResources.ER_CANT_HAVE_CONTENT_AND_SELECT,
                new Object[]{"xsl:" + this.getNodeName()});
            return null;
        }
        return super.appendChild(elem);
    }


}
